package cn.learn.domain.strategy.service.armory;

import cn.learn.domain.strategy.model.entity.StrategyAwardEntity;
import cn.learn.domain.strategy.model.entity.StrategyEntity;
import cn.learn.domain.strategy.model.entity.StrategyRuleEntity;
import cn.learn.domain.strategy.repository.IStrategyRepository;
import cn.learn.types.common.Constants;
import cn.learn.types.enums.ResponseCode;
import cn.learn.types.exception.AppException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.security.SecureRandom;
import java.util.*;

/**
 * @author Sun
 * @Desc  策略装配库(兵工厂)  负责初始化策略计算
 * @date 2024-10-25-21:00
 */
@Slf4j
@Service
public class StrategyArmoryDispatch implements IStrategyArmory,IStrategyDispatch{

    @Resource
    private IStrategyRepository repository;

    @Override
    public Boolean assembleLotteryStrategyByActivityId(Long activityId) {
        Long strategyId = repository.queryStrategyIdByActivityId(activityId);
        return assembleLotteryStrategy(strategyId);
    }

    @Override
    public Boolean assembleLotteryStrategy(Long strategyId) {
        //1、查询策略配置
        List<StrategyAwardEntity> strategyAwardEntities = repository.queryStrategyAwardList(strategyId);

        //2、缓存奖品库存 【用于decr扣减库存使用】
        for(StrategyAwardEntity strategyAward : strategyAwardEntities){
            Integer awardId = strategyAward.getAwardId();
            Integer awardCount = strategyAward.getAwardCount();
            cacheStrategyAwardCount(strategyId,awardId,awardCount);
        }

        //3.1 默认装配配置 【全量抽奖概率】
        assembleLotteryStrategy(String.valueOf(strategyId), strategyAwardEntities);

        //3.2、权重策略配置 - 适用于 rule_weight 权重规则配置
        StrategyEntity strategyEntity = repository.queryStrategyEntityByStrategyId(strategyId);
        String ruleWeight = strategyEntity.getRuleWeight();
        if(null == ruleWeight){
            return true;
        }

        StrategyRuleEntity strategyRuleEntity = repository.queryStrategyRule(strategyId,ruleWeight);
        if(null == strategyRuleEntity){
            throw new AppException(ResponseCode.STRATEGY_RULE_WEIGHT_IS_NULL.getCode(),ResponseCode.STRATEGY_RULE_WEIGHT_IS_NULL.getInfo());
        }

        Map<String, List<Integer>> ruleWeightValueMap = strategyRuleEntity.getRuleWeightValues();
        Set<String> keys = ruleWeightValueMap.keySet();
        for(String key : keys){
            List<Integer> ruleWeightValues = ruleWeightValueMap.get(key);
            ArrayList<StrategyAwardEntity> strategyAwardEntitiesClone = new ArrayList<>(strategyAwardEntities);
            strategyAwardEntitiesClone.removeIf(entity -> !ruleWeightValues.contains(entity.getAwardId()));
            assembleLotteryStrategy(String.valueOf(strategyId).concat("_").concat(key), strategyAwardEntitiesClone);
        }
        return true;
    }

    private void cacheStrategyAwardCount(Long strategyId, Integer awardId, Integer awardCount) {

        String cacheKey = Constants.RedisKey.STRATEGY_AWARD_COUNT_KEY + strategyId + Constants.UNDERLINE + awardId;
        repository.cacheStrategyAwardCount(cacheKey,awardCount);
    }

    private void assembleLotteryStrategy(String key,List<StrategyAwardEntity> strategyAwardEntities){
        //1、获取最小概率值
        BigDecimal minAwardTate = strategyAwardEntities.stream()
                .map(StrategyAwardEntity::getAwardRate)
                .min(BigDecimal::compareTo)
                .orElse(BigDecimal.ZERO);

        //2、获取概率值的总和
        BigDecimal totalAwardRate = strategyAwardEntities.stream()
                .map(StrategyAwardEntity::getAwardRate)
                .reduce(BigDecimal.ZERO, BigDecimal::add);

        //3、用 1 / 0.0001 获取概率范围。百分位 、 千分位 、 万分位
        BigDecimal rateRange = totalAwardRate.divide(minAwardTate,0, RoundingMode.CEILING);

        //4、生成策略奖品概率查找表 【这里指需要在list集合中，存放上对应的奖品占位即可，占位越多等于概率越高】
        ArrayList<Integer> strategyAwardSearchRateTables = new ArrayList<>(rateRange.intValue());
        for(StrategyAwardEntity strategyAward : strategyAwardEntities){
            Integer awardId = strategyAward.getAwardId();
            BigDecimal awardRate = strategyAward.getAwardRate();
            //计算出每个概率值需要存放到查找表的数量，循环填充
            for(int i = 0;i < rateRange.multiply(awardRate).setScale(0,RoundingMode.CEILING).intValue();i++){
                strategyAwardSearchRateTables.add(awardId);
            }
        }

        //5、对存储的奖品进行乱序操作
        Collections.shuffle(strategyAwardSearchRateTables);

        //6、生成出Map集合，key值，对应的就是后续的概率值。通过概率来获得对应的奖品ID
        HashMap<Integer,Integer> shuffleStrategyAwardSearchRateTable = new LinkedHashMap<>();
        for(int i = 0;i < strategyAwardSearchRateTables.size();i++){
            shuffleStrategyAwardSearchRateTable.put(i,strategyAwardSearchRateTables.get(i));
        }

        //7、存储到redis
        repository.storeStrategyAwardSearchRateTables(key,shuffleStrategyAwardSearchRateTable.size(),shuffleStrategyAwardSearchRateTable);
    }

    @Override
    public Integer getRandomAwardId(Long strategyId) {
        //分布式部署下，不一定为当前应用做的策略装配，也就是值不一定会保存到本地应用，而是分布式应用，所以需要从redis中获取
        int rateRange = repository.getRateRange(strategyId);

        return repository.getStrategyAwardAssemble(String.valueOf(strategyId),new SecureRandom().nextInt(rateRange));
    }

    @Override
    public Integer getRandomAwardId(Long strategyId, String ruleWeightValue) {
        String key = String.valueOf(strategyId).concat("_").concat(ruleWeightValue);

        //分布式部署下，不一定为当前应用做的策略装配，也就是值不一定会保存到本地应用，而是分布式应用，所以需要从redis中获取
        int rateRange = repository.getRateRange(key);

        return repository.getStrategyAwardAssemble(key,new SecureRandom().nextInt(rateRange));
    }

    @Override
    public Integer getRandomAwardId(String key) {
        //分布式部署下，不一定为当前应用的装配策略。也就是值不一定会保存到本地应用，而是分布式应用，所以需要从Redis中获取
        int rateRange = repository.getRateRange(key);
        //通过生成的随机值，获取概率值奖品查找表的结果
        return repository.getStrategyAwardAssemble(key,new SecureRandom().nextInt(rateRange));
    }

    @Override
    public Boolean subtractionAwardStock(Long strategyId, Integer awardId,Date endDateTime) {
        String cacheKey = Constants.RedisKey.STRATEGY_AWARD_COUNT_KEY + strategyId + Constants.UNDERLINE + awardId;
        return repository.subtractionAwardStock(cacheKey);
    }

}
